Fort LAUDERDALE, Fla. — Newt Gingrich appears headed toward a big defeat in Tuesday’s GOP primary in Florida. Five polls out Monday show Mitt Romney ahead of him by at least 5 percentage points (Insider Advantage) and as much as 20 points (Suffolk University). In the Real Clear Politics average of recent polls, Mr. Romney leads Mr. Gingrich by 12.5 points.

The polls reflect a stunning reversal of fortune for the former House speaker, who trounced Romney in the South Carolina primary only nine days ago by nearly 13 points. Gingrich is reacting defiantly, insisting that the Republican nomination race will go on all the way to the party’s convention in August.

Candidates in trouble always say they’re in it for the long haul. After all, why telegraph to your supporters that you may be a lost cause? And after Tuesday, only a tiny fraction of convention delegates will have been awarded.

But in Gingrich’s case, he may mean it. He has long dreamed of becoming president, and at age 68, this is likely his last chance to be taken seriously as a presidential candidate. But first, there’s the question of money.

“It is conceivable that Gingrich could stay alive but he has to replenish his campaign coffers first,” says Ford O’Connell, a former aide to the McCain campaign in 2008.

Enter Sheldon Adelson, the Nevada casino magnate, and his wife, who have already pumped $10 million into a pro-Gingrich super political-action committee that has funded ads highly critical of Romney. If the Adelsons re-up with another donation to Winning Our Future, that signals to potential Gingrich campaign donors that he’s still in the game.

As for his own campaign finances, Gingrich has already shown that he can live off the land. His role model could be Arkansas Gov. Mike Huckabee, who stayed in the 2008 campaign for weeks even after it was clear John McCain was going to win the Republican nomination.

Working against Gingrich is the lack of debates for the next three weeks. Debates have been his savior as they have allowed the cash-poor former speaker to shine in the national spotlight – for free.

True, he turned in weak performances in the last two debates, as Romney turned up the heat. But Gingrich now knows that he has to prepare for an energized Romney in the next debate, if he can hang on until then. It will be Feb. 22 in Mesa, Ariz.

The February primary and caucus calendar also works against Gingrich. Next up are the Nevada caucuses on Feb. 4, where Romney has an edge owing to the state’s large Mormon population. Texas Rep. Ron Paul has not been campaigning in Florida, instead working hard in Nevada, where he hopes to pick up some delegates.

Between now and Super Tuesday, March 6, all the contests are outside the South, Gingrich’s home base, where he hopes to do well. But even there, Gingrich’s low-budget campaign got caught unqualified for the ballot in Virginia, and so his name will not appear there and write-ins are banned.

Working in Gingrich’s favor is the rule change by the Republican National Committee that stipulates contests held before April 1 award delegates proportionally, not winner take all. Some states, such as Florida, are flouting that rule, but those that do award proportionally give Gingrich an opportunity to amass delegates.

His bigger obstacle could be the media narrative. If he loses Florida, as expected, he will have lost momentum – and he will face pressure with every subsequent contest to explain what he’s still doing in the race.

He does not have a lot of surrogates in the Republican establishment. So it could fall to people like former candidate Herman Cain, who endorsed Gingrich last Saturday, and Sarah Palin, who has not formally endorsed but sticks up for him on television, to help him make his case.

A wild card could be the tea party movement. Many of its leaders back Gingrich, and they could opt to step up their game in a united front against Romney, whom they see as an unprincipled moderate.

In the end, Gingrich may feel personal financial pressure to drop out after a certain period. If he wants to return to his life as a consultant in Washington, he may not want to anger the GOP establishment too much by dragging on a nasty confrontation with Romney.